shee Acted No. et September 20, 1921. 


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% 6 s/4: y: COMMONWEALTH OF PENNSYLVANTA 
BuUL ZI 


DEPARTMENT OF INTERNAL AFFAIRS 
James F. Woodward, Secretary 


BUREAU OF TOPOGRAPHIC AND GEOLOGICAL SURVEY 
George H. Ashley, State Geologist | 








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FBRIDSPAR IN PENNSYLVANIA 
By. 
George H. Ashley 


“-Beldspar Ls) one. or Mie minor minerals produced ey Pennsylvania. 
The ‘Statets output in 1920. as ancien by the Ue S. Geological Sur- 
Nres was ‘8, San) tons valued at $81,104. re ant came from the south- ,, 
eastern part of the State, and chiefly from ghestet and Bataware | 
counties. | 
Feldspar is used very extensively in the manufacture of china 
and porcelain to influence the character of the "mix" as to ey 
Weay. etc. Its melting point being lower than that of the other 
Sebitaanta, it serves as a flux to. bind the particles of clay and , 
ig quartz hioee shat. It has been used a little as a source of aluminum 
and Seat though hardly with commercial success, It is also used 
as a binder in making emery wheels; in the manufacture of certain 
‘Kinds of gless and enamels; and as a polishing or scouring medium. 
Being a little less gritty than silica or ground sand, it is suited 


for use in scouring Soap. 


Feldspar is a general name for a group of minerals, all of which 


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“gpotain aluminum, silicon, anda Biygen: and in varying Eianbiees Des 
two of the elements, pate tn: pete eta: and sodium, Some of the 
feldspars known as Amazon Bevel bab eecne: and sunstone are used as 
eems. All-three of these gem stones have been found at Mineral Hill 
in Delaware County. 

Peldspar is one of the three principal minerals composing gran- 
ite and it occurs in crystals in other rocks. The commercial de - 
posits, however, occur in the form of pegmatite dikes and veins, 

Most of the deposits are of the usual type of eranite-pepematite, but 
those in the extreme southwest part of Chester County belong to an 
entirely eRe tare nwt ype: which may be designated soda pegmatite, its 

“principal mineral being the soda feldspar, albite. This variety con- 

tains no Mee) oc : 7 | 

The ‘Qikes, or ‘veins that have been age are 6 to 25 feet wide 


and in most places. the - feldspar, fitien is cream to pink or flesh - 


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colored,” wae in etystals that, are from oe inch eo 2 inches BCTOSS. © 
In some. places pire: ‘orystals’l ie a ad Foot. in: diameter eee been found. 
The places where Poldspar has been maped. in the past and is still to 
be found are along a line from the Leiperville quarries near Ghanvaus 
to Upland and Avondale, and in general along Plum Creek in Delaware 
County. In Chester County it occurs in many localities, as at Union- 
pie. eervaniee West Chester , and at Brinton's quarry. It occurs 
in a more or less disconnected line from West Philadelphia to Frank- 
ford; and from Germantown and Chestnut Hill to the Schuylkill. In 
recent years it has been mined at Avondale, Toughkenamon, Chatham, 
New Garden and at West Caln near the Maryland line in Chester County; 


at Blan in Delaware County; and several places in Montgomery County. 


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